Homework Problem Set 11 Iverson CH320N Due Friday, May 5

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1 omework Problem Set 11 Iverson 320 Due Friday, May 5 AME (Print): SIGATURE: hemistry 320 Dr. Brent Iverson Problem Set 11 April 28, 2017 Please print the first three letters of your last name in the three boxes 1

2 omework Problem Set 11 Iverson 320 Due Friday, May 5 Score: 2

3 omework Problem Set 11 Iverson 320 Due Friday, May 5 1. For the following carbohydrates, draw a circle around all of the D-carbohydrate(s), and draw a rectangle around all of the L-carbohydrate(s). n the two first two lines below the four structures, indicate whether each is an aldose or ketose, and whether each is a pentose or hexose, respectively. n the third line below each structure, construct a compound name from all of these elements. For example, answers might be L-ketopentose or L-aldohexose. Finally, on the fourth line under each structure write the specific name (i.e. D-glucose) for each structure. You should use table 25.1 or other structures named in the book to identify these exact sugar names. (You will T need to know them for the test) (aldose or ketose?) (pentose or hexose?) (compound name) (exact name) (look up but don t memorize) 2 2 For the disaccharide of glucose on the left, draw a circle around any glucose residue that is/are α. Draw a box around any glucose residue that is/are β. ext, draw a box around the glyocosidic bond linkage. Finally, circle all anomeric carbon atoms. Describe the above linkage using the terminology presented in class: 3

4 omework Problem Set 11 Iverson 320 Due Friday, May 5 2. Many of the reactions we have learned this semester involve steps with nuclephiles reacting with electrophiles. For the following examples of steps in mechanisms we have seen this semester, 1) Draw the intermediate that will be formed when the two molecules react. 2) Draw all formal charges and lone pairs on the intermediates. 3) Draw arrows on the starting materials to indicate the flow of electrons that leads to the intermediate. 4) Finally, draw a box around the nucleophile and a circle around the electrophile in each case. There is no need to draw products or any further steps of the mechanisms. You might want to read these directions again so you know what we want. A) Intermediate B) l Intermediate ) 2 P(Ph) 3 Intermediate D) Intermediate E) F 2 Intermediate 4

5 omework Problem Set 11 Iverson 320 Due Friday, May 5 3. omplete the mechanism for the following aldol reaction. Be sure to show arrows to indicate movement of all electrons, write all lone pairs, all formal charges, and all the products for each step. Remember, I said all the products for each step. IF A EW IRAL ETER IS REATED I A ITERMEDIATE R TE PRDUTS, MARK IT WIT A ASTERISK and WRITE RAEMI IF RELEVAT. In the boxes provided adjacent to the first two sets of arrows, write which of the four basic mechanistic elements are involved (i.e. "Make a bond", "Add a proton", etc.) Products 5

6 omework Problem Set 11 Iverson 320 Due Friday, May 5 4. omplete the following mechanism for the Michael reaction. Make sure to show all lone pairs, all formal charges and use arrows to indicate the flow of all electrons. You must draw all products that are made in each step. This should look familiar, as it is identical to the mechanism sheet handed out in class. In the boxes provided adjacent to the arrows, write which of the four basic mechanistic elements are involved (i.e. "Make a bond", "Add a proton", etc.) Michael Reaction 1 Equivalent (aet) Michael Reaction tautomerization Products 6

7 omework Problem Set 11 Iverson 320 Due Friday, May 5 7

8 omework Problem Set 11 Iverson 320 Due Friday, May 5 6. Fill in the box with the product or products that are missing from the following chemical reaction equations. When a racemic mixture is formed, you must write "racemic" under both structures EVE TUG YU DREW BT STRUTURES. 3 heat Sl 2 1) uli 2 2) 2 2 eq. 1) 2) l / 2 MgBr 1) LiAl 4 2) 2 8

9 omework Problem Set 11 Iverson 320 Due Friday, May 5 7. In the boxes provided, write the hybridization state of the given atoms In the boxes provided, according to the valence bond approach, write the type of atomic orbital that contains the indicated lone pair of electrons

10 omework Problem Set 11 Iverson 320 Due Friday, May 5 i 10

11 omework Problem Set 11 Iverson 320 Due Friday, May A) n the upper lines, rank the following with respect to relative anion stability, with a 1 under the least stable anion (i.e. most reactive with a proton) and a 4 under the most stable anion (i.e. least reactive with an proton). n the lower lines, rank the following with respect to leaving group ability, with a 1 under the worst leaving group, and a 4 under the best leaving group. Anion Stability 3 2 l 3 2 Leaving Group Ability B) Rank the following in terms of relative reactivity with a nucleophile without acid catalysis. Place a 1 under the least reactive and a 4 under the most reactive species. 3 3 l 3 l In each of the boxes over an arrow, write the minimum number of equivalents of the specified reagent required to carry out the reaction shown to completion. If only a catalytic amount is needed, write "AT". ote: You must assume the carbonyl compound starting material is initially present in an amount of 1.0 equivalent. A) 3 1) 2) mild 3 equivalents 3 a * 3 (racemic) B) 3 1) equivalents LDA 3 ) equivalents a * (racemic) 11

12 omework Problem Set 11 Iverson 320 Due Friday, May You might find these are harder so take your time. Write the predominant product or products that will occur for each transformation. If a new chrial center is created and a racemic mixture is formed, mark the chiral center with an asterisk "*" and write "racemic" under the structure. If ortho/para products are made, you must draw both. ote, for this problem, aldols can dehydrate if heated in dilute acid. 2 Br 2 / FeBr 3 Br 2 / FeBr 3 Assume only one Br atom adds 1) cat. a 2) 3 / heat Be sure to indicate stereochemistry of the products on this next one. 1) 1.0 Eq. aet 2) Br 3) 3 / heat 12

13 omework Problem Set 11 Iverson 320 Due Friday, May Show reagents and intermediates synthesized along the way that allow you to produce the product from the given starting material. Assume you can isolate either the ortho or para product in pure form, even though both are usually produced together. (13 pts)? I Br 13

14 omework Problem Set 11 Iverson 320 Due Friday, May Using any reagents turn the starting material into the indicated product. All the carbons in the product must come from the given starting materials. Draw all molecules synthesized along the way. When it doubt, draw the molecule! TE: For this one, you are not allowed to separate complex mixtures along the way and pull out just the isomers you want. In other words, the product isomers shown must be the only predominant isomers you make during your synthesis. (16 pts)? l Br l Br 14

15 omework Problem Set 11 Iverson 320 Due Friday, May Show reagents and intermediates synthesized along the way that allow you to produce the product from the given starting material. Assume you can isolate either the ortho or para product in pure form, even though both are usually produced together. (19 pts) 2 + K? l 2 15

16 omework Problem Set 11 Iverson 320 Due Friday, May Using any reagents turn the starting material into the indicated product. All the carbons in the product must come from the given starting materials. Draw all molecules synthesized along the way. When it doubt, draw the molecule! ote, for these last two, you might not need to use all three starting materials (34 pts) a? 16

17 omework Problem Set 11 Iverson 320 Due Friday, May Using any reagents turn the starting material into the indicated product. All the carbons in the product must come from the given starting material or starting materials. Draw all molecules synthesized along the way. When it doubt, draw the molecule! (23 pts) 3? 17

18 omework Problem Set 11 Iverson 320 Due Friday, May Using any reagents turn the starting material into the indicated product. All the carbons in the product must come from the given starting material or starting materials. Draw all molecules synthesized along the way. When it doubt, draw the molecule! (21 pts)? 18